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AMD Radeon R9 and R7 Graphics Unleashed

By Vijay Anand - 8 Oct 2013

AMD Radeon R9 and R7 GFX Unleashed


Meet the New Radeon R9 and R7 Series

Expecting a Radeon 8000 series of graphics cards? Well, if you’ve missed our update from last month, AMD has decided to skip the conventional four-digit naming scheme to something you might be familiar when browsing AMD APU processor models where there are two descriptors to help carve out the product lineup. AMD seems to think that the new Radeon R9 and R7 graphics cards pack enough firepower and new features to warrant a differentiation noteworthy of the change it hopes to bring for the gaming scene and the name change was part of the plan to keep things fresh.

We’ll get to the details of what makes the new graphics cards tick and outshine its predecessors, but before that, it’s time to get a quick overview of the new series that will soon be available this month. Though the AMD Radeon R9 series is targeted at enthusiasts and the R7 is tailored for mainstream gamers, if AMD keeps its promise, consumers should be able to get stocks of both varieties in the channel through staggered introduction throughout this month in October. 

Take note that at the time of publication, the top of the line Radeon R9 SKU is still under embargo till a later date. That aside, here's a broad overview of the various new Radeon GPU SKUs and how their basic configuration differs:-

AMD Radeon R9 and R7 GPUs Compared
Model AMD Radeon R9 290X / 290 AMD Radeon R9 280X AMD Radeon R9 270X AMD Radeon R7 260X AMD Radeon R7 250 AMD Radeon R7 240 AMD Radeon HD 7970 GHz Edition
Core Code  Hawaii  Tahiti XT variant Pitcairn XT variant Bonaire variant Cape Verde LE TBD  Tahiti XT
Transistor Count  > 6000 million 4300 million TBD TBD TBD TBD  4300 million
Manufacturing Process 28nm 28nm 28nm 28nm 28nm 28nm 28nm
Core Clock TBD Up to 1000MHz Up to 1050MHz Up to 1100MHz Up to 1050MHz Up tp 780MHz 1050MHz
Compute Performance > 5 TFLOPS 4.1 TFLOPS  2.69 TFLOPS  1.97 TFLOPS  806 GFLOPS 499 GFLOPS  3.79 TFLOPS
Stream Processors TBD 2048 1280 896 384 320 2048
Texture Mapping Units (TMUs) TBD 128 80 56 24 TBD 128
Raster Operator units (ROP) 64 32 32 16 16 TBD 32
Onboard Memory 4GB GDDR5 3GB GDDR5  2GB / 4GB GDDR5  2GB GDDR5 1GB GDDR5 / 2GB DDR3   1GB GDDR5 / 2GB DDR3 3GB GDDR5
Memory Clock TBD 6000MHz 5600MHz 6500MHz 4600MHz 4600MHz 6000MHz
DDR Memory Bus TBD 384-bit 256-bit 128-bit 128-bit 128-bit 384-bit
Memory Bandwidth TBD 288GB/s 179.2GB/s 104GB/s 73.6GB/s 73.6GB/s 288GB/s
PCI Express Interface PCIe ver 3.0 x16 PCIe ver 3.0 x16 PCIe ver 3.0 x16 PCIe ver 3.0 x16 PCIe ver 3.0 x16 PCIe ver 3.0 x16 PCIe ver 3.0 x16
Molex Power Connectors 1 x 6-pin, 1 x 8-pin 1 x 6-pin, 1 x 6-pin 2 x 6-pin 1 x 6-pin N.A. N.A. 1 x 6-pin, 1 x 8-pin
Typical Board Power TBD 250W  180W  115W 65W   30W 250W
Multi GPU Technology Improved AMD CrossFire CrossFireX CrossFireX CrossFireX N.A. N.A. CrossFireX
Display Connectivity
  • 2 x Dual-Link DVI
  • 1 x HDMI
  • 1 x DisplayPort
  • 2 x Dual-Link DVI
  • 1 x HDMI
  • 1 x DisplayPort
  • 2 x Dual-Link DVI
  • 1 x HDMI
  • 1 x DisplayPort
  • 2 x Dual-Link DVI
  • 1 x HDMI
  • 1 x DisplayPort
  • 1 x Dual-Link DVI
  • 1 x HDMI
  • 1 x VGA
  • 1 x Dual-Link DVI
  • 1 x HDMI
  • 1 x VGA
  • 1 x Dual-Link DVI
  • 1 x HDMI
  • 2 x mini-DisplayPort (mDP)
AMD TrueAudio Technology Yes No No Yes No No No
API Support DirectX 11.2, OpenGL 4.3, AMD Mantle DirectX 11.1, OpenCL 4.2
Launch Price TBD US$299 US$199 US$139 < US$89 TBD US$549
(Current street price: ~US$299)


Product Positioning of the new Radeon Series

To sum up all of the new offering neatly, the new Radeon R9 270X is designed for the best gaming quality at 1080p resolution (1920 x 1080 pixels), while the R9 280X is targeted at gamers using existing large screen monitors and high resolutions like 2560 x 1440 pixels, and the R9 290 series is built for individuals who’ll settle nothing less than gaming in 4K resolution with the very best monitors available in the market. The entire R7 series is made for price-conscious upgraders moving from integrated graphics or replacing older graphics hardware but welcome the modern features of the new GPUs. 

What you should really be aware is that the brand new "Hawaii" GPU core is only featured on the Radeon R9 290 series. For the Radeon R9 280 series and lower, you'll notice that AMD has rehashed their existing GPU cores from the Southern Island GPUs. An exception is for the Radeon R7 260X that will feature a new ASIC to support a new hardware feature - AMD TrueAudio Technology. We cover more about this feature on the next page, but as for the R7 260X GPU core, it's still using the same GCN architecture from the Radeon HD 7000 series.

When we asked AMD of the reasons behind the new naming scheme, they pin it squarely on their new marketing and initiatives for the GPU division as a whole and thus a new brand name to reflect this change. Primarily, AMD is working more with game developers and making waves in the gaming industry with their new Mantle API initiative. While that bodes well with AMD's directions, this will undoubtedly cause some confusion with end-users who expect a radical change when they purchase newly branded products and not variations of existing products. Only time will tell how this might pan out.


At the Core of Things - An Updated GCN Architecture

Last generation’s Southern Island GPUs have made significant changes to the graphics processing architecture that debuted as the Graphics Core Next (GCN) architecture. The new Hawaii-core based GPU that will be featured on the Radeon R9 290 series take it up a notch with further refinements and an updated core layout to account for even more firepower. Unfortunately, at the time of publishing this, the detailed information about the R9 290 series is still under NDA and that prevents us from sharing a lot of interesting tidbits of the new architecture.

Despite that, we’ve spent some time studying the details of the core such that we’ll present you aspects that don’t yet infringe on the NDA. For starters, the core processing unit in any of AMD’s modern GPU is a GCN compute unite (CU). This has largely remained identical to that of the GCN CU of the Southern Island GPUs (Radeon HD 7000 series), but has a few updates such as support for a Flat Addressing support that now allows the hardware to determine direct addressing, improved media processing instruction support – especially to the Maskable Quad Sum of Absolute Difference (MQSAD) that was introduced in the previous generation whose function is to allow background pixels to be ignored while helping isolate moving objects. So yes, on the whole each GCN CU still has quad 16-processing element vector units, which gives you 64 stream processors per GCU block (or per GCN CU).

The Radeon R9 and R7’s GPU compute unit (CU) largely remains similar the previous generation, but what differs is the number of compute units available per GPU. This also means the number of other supporting processing engines and blocks that co-work with the basic GCN compute unit also differs in each GPU configuration.

What has changed is the number of GCN compute units that the entire GPU has in each of the R9 and R7 models, which brings about the differentiated number of stream processors available (as tabulated above). Supporting the graphics processing blocks is other functions like the rasterizer, render back-ends, geometry processors, L2 cache and the memory interface – all of which have been incrementally updated but the biggest change is the allocation of the number of units per shader engine block. We’ll detail this when we’ve obtained clearance, but two aspects that have been publicly acknowledged is the doubling of the render back-ends on the top tier R9 290 series (to cater to 4K resolution gaming) compared to the Radeon HD 7970 and the much higher density memory interface used on the new R9 and R7 GPUs that consume much less die space in a bandwidth per mm2 dies size used.

The new R9 and R7 series of GPUs are still manufactured based on the 28nm processing node, but given all the enhancements and increased number of processing units/blocks and other other aspects, the top-end R9 290 series carries over 6 billion transistors and naturally a larger die size compared to its predecessor. Despite that, AMD assured us that the R9 290 series uses 25% less die size compared to NVIDIA’s Titan and is more efficient per mm2 die size (though there’s no mention of how the performance will stack up).

While details of the Radeon R9 290 series are still under wraps, we’ve enough information to detail where the Radeon R9 280X stands, the next best in the line-up from AMD. As you can see from the tabulated comparison, the R9 280X comes up as a close contender with the Radeon 7970 GHz edition. In fact from our testing of an ASUS R9 280X OC graphics card, we found both of them performing rather similarly that the new R9 280X seems to be a direct replacement to the long running Radeon 7970 (both in price and performance).


Power to the People - A New PowerTune for 2013/2014

AMD’s PowerTune technology is the company’s version of the more popular GPU Boost used on NVIDIA’s products – even though AMD debuted this technology earlier. Essentially, AMD PowerTune that is featured on the previous generation Southern Island GPUs (Radeon HD 7000 series) analyzes the ‘active power signature’ of the card to utilize the unused thermal headroom. This is because most use-case scenarios hardly approach the graphics card’s TDP and technologies like AMD PowerTune help utilize balance power budget to push the core clock speeds and provide enthusiasts with increase performance.

The design goals of the new AMD PowerTune on AMD Radeon R9 and R7 graphics cards.

After more than 1.5 years since the Radeon HD 7970 first debuted, we’re glad to know that the Radeon R9 290 parts will also feature a much more comprehensive PowerTune technology, more so because NVIDIA’s GeForce Boost 2.0 in its current generation of offerings has been available since earlier this year. As painted in AMD’s PowerTune manifesto, it aims to be the most advanced controller to-date as it will now not only factor active power consumption, but also factor in other attributes such as real-time temperature monitoring, voltage draw and even fan speed.

As shown in the block diagram above, a Digital Power Management (DPM) arbitrator checks on the card’s temperature, power consumption and voltage draw to determine how best to increase another attribute to maximize the potential of the hardware. Factoring temperature targets (default threshold set at 95 degrees Celsius) and fan noise are the newer aspects of the new PowerTune architecture to provide more control and optimization. For the longest time, we’ve been complaining about the AMD reference coolers being rather noisy when we’re in the thick of gaming. Fortunately, the ability to set fan speed to your preference helps one control the optimal acoustics of the card and also ensures there’s no drastic changes in noise levels as the card enters various stages of usage.

At the end of the day, overall performance of the Radeon R9 and R7 graphics cards are determined by the overall balance power budget available and due to the dynamic nature and the various parameters that are in control by PowerTune (and further user inputs), AMD is officially acknowledging that the R9 and R7 cards will no longer have a single advertised clock speed but they will be advertised as “Up to xxxxMHz”. This is again noticeable by the large specs table we’ve tabulated above that reflects this change of marketing.

The 4 pillars of the new AMD PowerTune that’s featured in the Radeon R9 and R7 graphics cards.

Alas, all of this is playing catch-up as NVIDIA’s GPU Boost 2.0 and partner utilities have supported all of these in the GeForce 700 series of graphics cards from earlier this year. Nevertheless, it’s good to know AMD recognizes what needs to be done to appeal to the modern gamer. Performance numbers isn’t everything as the overall user experience is important too. Having said that, we notice that AMD hasn’t talked about any improvements to the cooler/shroud/fan used and we suspect that without the updated PowerTune, perhaps the reference cards will once again rear their ugly side of the previous generation Radeon cards. We’ll find out when and if we get hold of a reference-based Radeon R9 graphics card (at this point of time, we’re receiving a number of custom designed editions for evaluation from the usual suspects).

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